This is a simulation of a planet orbiting a sun. Initial conditions can be adjusted.
Use the sliders to adjust the initial speed of the planet, the initial distance from the center of the planet to the center of the sun, and the mass of the sun. Hit run to see the orbit animate. The orbit will be with elliptical, circular, parabolic, or hyperbolic, depending on the initial conditions. Show the Kepler's 2nd Law of planetary motion trace to see the elliptical orbit broken into eight wedges of equal area, each swept out in equal times.